Stones  

A minimum Gathering skill of 240 is required to harvest this node.

This special tradeskill quest resource node can only be seen by players that have one of the quests from the Grobb Daily Supply Tasks Mission Group, and are found all over the artisan area of Grobb.

Each harvest yields 3 swamp-smooth pebbles. Each node may be harvested 3 times.

A complete guide to harvesting can be found at A Harvester's Guide.